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What is a Flue Cap?

Lori Kilchermann
Lori Kilchermann

A flue cap is installed on the top of a chimney, and it prevents rain from flowing into the chimney as well as animals and birds from entering. A flue cap is typically made of sheet metal and some type of screen. They can be easily removed to clean the chimney and are available in many styles to compliment a home's decor.

When choosing a flue cap, decide on the style that best compliments the home. They can be created with black finishes as well as brass or bright finishes. On chimneys that will be used for wood burning, a larger and more open flue cap is usually chosen. On gas chimneys or on chimneys that are no longer used, a smaller opening can be used.

Sheet metal is commonly used to make a flue cap.
Sheet metal is commonly used to make a flue cap.

The larger opening allows the wood-burning furnace or fireplace to have a better draft. This creates a chimney with less back flow, which means less smoke in the house. A flue cap with a larger opening also creates a better escape of wood smoke which means less creosote build-up in the chimney. Creosote is the product that is often responsible for chimney fires.

Failure to install a cap on a chimney can result in birds nesting inside of the chimney. Bird nests create a fire hazard as well as prevent the gasses and smoke from exiting the chimney. This can cause damage to the home as well as death to the inhabitants of the home. Along with birds and squirrels, debris such as leaves and branches can also create a blocked chimney.

When installing a flue cap, always follow the manufacturer's directions for mounting. Ensure that a proper space has been allowed for exiting smoke and gas. Be certain that the cap is mounted securely. Wind can easily blow a poorly mounted flue cap off of a chimney. This could lead to other damage or injury if the cap is blown into another part of the house or yard.

Rain and snow can cause damage to a chimney. The flue cap prevents rain and snow from entering the chimney directly, which helps to prevent some damage. Rain settling into cracks in a chimney or its flues can freeze. This ice can crack a flue, creating a hot spot. The hot spot can lead to a chimney fire.

It is important to keep a chimney clean and one of the easiest ways to accomplish this is to install a flue cap. By preventing access to the chimney, birds, animals and debris will be less likely to create problems for the homeowner. With its added style, the cap can improve the appearance of the home and the money saved from chimney repairs can be better spent elsewhere.

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    • Sheet metal is commonly used to make a flue cap.
      By: Kybele
      Sheet metal is commonly used to make a flue cap.